Histogram data collector for applying progressively adjusted histogram equalization to an oscilloscope image

Abstract

A system is disclosed for equalizing the distribution of pixel intensities in an image displayed by an oscilloscope. In a primarily software implementation, the maximum pixel intensity (I) present in the rasterized input image, the maximum available display intensity (P) and the desired image resolution (R) are the input variables which permit the calculation of thresholds or bins to which each pixel is assigned. By iteratively performing the analysis of existing pixel intensities and bin thresholds, the number of pixels in each bin may be optimized to form an equalized histogram. Another implementation of the histogram equalization system utilizes software to optimize a hardware-based histogram collector.

Description

CLAIM OF PRIORITY[0001]This application is based on and claims priority from U.S. Provisional Application Ser. No. 60 / 356,883, filed on Feb. 12, 2002.FIELD OF THE INVENTION[0002]The subject invention relates generally to the field of oscilloscope display systems, and more particularly to an oscilloscope employing and displaying histograms.BACKGROUND OF THE INVENTION[0003]Current oscilloscopes can display images of waveforms derived from an internal image which may possess a large dynamic range of pixel intensities. Although the variation in pixel intensity of the internal image may be large, the actual display of this image limits the intensity range and therefore does not fully reflect all of the information contained in the internal image. An example of an oscilloscope which illustrates this problem is disclosed in U.S. Pat. No. 5,986,637 entitled DIGITAL OSCILLOSCOPE ARCHITECTURE FOR SIGNAL MONITORING WITH ENHANCED DUTY CYCLE, issued to Etheridge et al. The Etheridge et al. devic...

AI Technical Summary

Benefits of technology

[0009]The present invention addresses the problem of applying histogram equalization to an oscilloscope waveform display. The dynamic range of display intensities is more fully utilized. This allows the user to more easily discern the difference in intensities between pixels, the pixels indicating the frequency or magnitude of rasterized image data.

[0012]Mapping of the input image to a smaller dynamic range can occur simultaneously with the collection of histogram data, or mapping can occur without writing to memory, or only collection of the histogram information can occur. The histogram equalization function adjustment algorithm is applied to an oscilloscope image to improve the equalization properties of the mapping function. The new mapping function is then applied to the next image to be mapped. The assumption is made that the next image will be similar to the previous image or at least possess the same input histogram properties. This assumption and the prediction of the histogram properties of subsequent images saves processing time as a separate histogram collection function does not need to be executed. Typically the histogram collection of the current image is done while mapping the current image for display.

Problems solved by technology

Since a histogram of the output image cannot fully represent all the information of a histogram of the input image, any mapping function generated from the output image may not precisely equalize the histogram.

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